1. Field of the Invention
The present invention relates to an epoxy resin composition which is useful for adhesives, coating materials, electric and electronic materials such as insulating materials and laminated plates, particularly useful to encapsulate electronic parts, and excellent in preservation stability, and a process for producing the same.
2. Description of the Related Art
An epoxy resin is used generally as a resin composition, by being mixed with a curing agent, a cure accelerator, a filler, etc., and the composition has a problem of preservation stability. In recent years, transfer molding of an economically useful epoxy resin composition has been performed for encapsulating semiconductors, such as LSI, IC, and a transistor, and in this field, the preservation stability is especially important in view of productivity and economical efficiency.
However, the preservation stability of the conventional compositions has not been sufficient. Especially in case of using a crystalline epoxy resin, when the crystallinity is lost in a kneading process, the softening point of the composition falls remarkably, and the preservation stability is remarkably lowered. For this reason, the composition is necessary to be stored cool until just before molding. If it is left at room temperature for some time, it may become unusable.